USF geologist says catastrophic sinkholes are rare

WEST CHASE, Florida - As more and more sinkholes open up in the Bay area, some are asking why here, why now, and what causes them?

USF geologist Dr. Mark Stewart says catastrophic sinkholes are rare. He says since 1968, the last 45 years, there have been four sinkhole related deaths in Florida. Every year, 8 to 10 people die from a lightning strike. While geologists say they know where sinkholes are likely to happen, they can't predict when.

"I'm scared after what happened last week. It can happen to anybody," says Herman Cruz. He and his wife, Waleska, say it happened to them three years ago when a sinkhole opened up under their West Chase home.

"My wife heard cracking noise in the house," recalls Herman.

"I hear it stretching in the middle of the night. He thought I was crazy hearing stuff," says Waleska.

"She wasn't," says Herman.

Stretching sounds turned into a water leak that warped the wood floor and left cracks in the exterior and interior walls. Some cracks are still visible in the garage wall and along the floor reaching out to the sidewalk. The cost to repair? $110,000, says Herman.

Homeowner's insurance covered it, but that's not what worried Herman. "The trouble, loss of my home, family. Where are we going to go?" says Herman.

RAB Foundation Repair filled the sinkhole within 30 days. "They did a great job," says Herman. He was surprised to see four to five trucks of concrete show up to fill the void under his home.

"There are lots of sinkholes waiting to open up," says USF professor and geologist Doctor Mark Stewart, PH.D. Stewart says west Central Florida is primed for sinkholes. A geological map of Florida shows sinkholes are most reported between Orlando and the west coast and up through Citrus County.

"We have limestone at shallow depths covered with 30-100 feet of loose sediment. That is a condition that makes sinkholes more likely," describes Stewart.

The same map shows how the ground makeup changes a few miles south of the Bay area. There are only a few sinkholes reported from Manatee County on south.

While sinkholes happen naturally, Stewart says man can trigger them. He says, "There's an increase of sinkholes in May, not because of the dry conditions, but because we pump more ground water. Pumping ground water is a potential trigger for sinkhole."

10 News gave the Cruz's a closer look at the sinkholes in the Tampa Bay area. The Hillsborough map shows a heavy concentration of sinkholes from the center of the county to the west and northwest areas. "Wow! We're right in the worst spot," says Herman.

If Herman had seen the map eight years ago, would he have bought his house in West Chase? He says, "No, just because of the safety of my family."

Stewart says there is no good data keeping for sinkholes; it's all voluntary. While we are seeing more sinkholes, he says it's because more are being reported as more people move into sinkhole prone areas.

Between 2006 and 2011, there were $1.4 billion in damages reported and 6,000 claims filed.